This invention relates generally to a process of leaching chloride ions from ores containing copper as oxides. More particularly, the invention relates to a process for leaching chloride ions from ores containing atacamite/paratacamite utilizing an aqueous solution of the basic salt of a Group I-A or Group II-A metal.
Copper minerals in the oxidized zone of porphyry copper deposits are categorized broadly as copper "oxides". These oxides include atacamite/paratacamite [Cu.sub.2 (OH).sub.3 Cl], azurite/malachite [Cu.sub.3 (CO.sub.3).sub.2 (OH).sub.2 /Cu.sub.2 (CO.sub.3) (OH).sub.2 ], chrysocolla [CuSiO.sub.3.nH.sub.2 O], cuprite [Cu.sub.2 O], etc. The copper minerals in the underlying sulfide rich and primary sulfide zones include chalcocite [Cu.sub.2 S], chalcopyrite [CuFeS.sub.2 ], and bornite [Cu.sub.5 FeS.sub.4 ].
The alteration of atacamite by KOH solution to hydrous cupric oxide is reported in "The System of Mineralogy", Charles Palache et al., John Wiley & Sons, Inc., Volume II, 1951 at page 72, citing Chumanov, J. Russ. Phys. Chem. Society, 47, 1268 (1915). This proposal, however, has not found commercial acceptance.